"Escape the Room" games are a preset number puzzles that a group of people have to solve to ta da! Escape the room.
Think "Myst" or any of the Text based adventure games (eaten by a gru!!!), and there are plenty of mobile and web based ones out there as well - Except this is real. with real locks, puzzles that you have to manipulate, tools that you find in one part of the game have to be used for another.
These venues are all themed to each escape scenario - in the one I went to it was themed as a lab, with a desk, filing cabinet, xray viewer, secure sample box, then the next room that you got into (after solving certain puzzles- a magnetic lock opened a secret door) was like a industrial basement with pipes and grating. and more puzzles to solve to finally get out. Lots of micro controller usage with magnetic locks, LED displays, relays to turn on a black light when you completed a puzzle to reveal another clue, hall effect switches as well as physical locks.
It was really challenging, but we all had to work together and solve each puzzle, so it was collaborative and fun. It taught perseverance and the timer on the wall gave the whole thing a sense of urgency. Yes we got out with 7 mins to spare.
I wasn't alone. Someone has already done the hard work... and it is open source (free)
It's a real world puzzle platform you can use to run free pre-made games for your students, plus a template to make your own. It can integrate both real world and ICT puzzles via website, QR codes or images.
You either buy the "box" of locks or make your own according to the specifications. There is also a low cost Lock app that you can use to create virtual locks.
There is a big element of STE(A)M with this and you could extend the puzzles with arduino or probably more beneficial - get the students to create their own scenarios and puzzles.
Anyway - if you were looking to do something cool with your middle schoolers at the end of the year - this is not a bad option.